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(No Model.) 3 Sheets-Sheet 1.

F MOSSBERG.

TWIST DRILL GRINDING ATTACHMENT.

No. 389,095. Patented 8 pt. 4, 1888. z m I WIIT'LE S55E51, ITIVETLIDT,

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3 Sheets-Sheet 2.

(No Model.) 8

P. MOSSBERG. 7 TWIST DRILL GRINDING ATTAGHMENT. No. 389,095. Patented Sept. 4, 1888.

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F. MOSSBERG. TWIST DRILL GRINDING ATTACHMENT.

No. 389,095. Patented Sept. 4 1888.

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UNITED STATES PATENT EEicE.

FRANK MOSSBERG, OF PAWTUCKET, RHODE ISLAND.

TWIST-DRILL=GRINDING ATTACHMENT.

SPECIFICATION forming part of Letters Patent No. 389,095, dated September 4, 1888.

Application filorl January 17, 1887. Serial No. 224,632. (No model.)

To all 1071,0722 it may concern.-

Be it known that I, FRANK Mossnnne, of Pawtucket, in the county of Providence, in the State of Rhode Island, have invented a certain new and usefulImprovementin Twist- Drill Grinding Attachments; and I declarethe following to be a specification thereof, reference being had to the accompanying drawings.

Like letters indicate like parts.

Figure 1 is a side elevation of my improved grinding attachment for twist-drills. Fig. 2 is a top plan of the same. Fig. 3 shows the same, partly in elevation and cross-vertical section, on the line a: of Fig. 2. Fig. 4 is an end view in elevation, as seen from the lefthand end of Fig. 2. Fig. 5shows a top plan of my twist-drill-grinding attachments mounted upon an emery-wheel grindingmachine. Fig. 6 shows, respectively, in rear end elevation, side elevation, and top plan, the gage foradj usting the drill in the grinding position. Fig. 7 is a side elevation of the supplemental drillholding device. Fig. 8 is a cross section on line a." oi Fig. 10. Fig. 9 is an end view of the said supplemental drill-holder. Fig. 10 is a top plan of the same. Fig. 11 is a side elevation of the spring in the same. Fig. 12 illustrates in top plan the position of the same when in use. Fig. 13 is a cross-section on line :0 of Fig. 15. Fig. 14 is a rear elevation of the head-piece and some of its connected parts. Fig. 15 is a crossscction online of Fig. 14.

My invention relates to attachments for grinding twist-drills upon emery-wheels; and it consists of certain improvements in the details of the machine described in my applica tion for Letters Patent of the United States, Serial No. 215,508,now pending, as well as of additional devices in connection therewith for the more accurate and convenient manipulation of the drill while in process of grinding its lips and point, as hereinafter particularly described, and specifically pointed out in the claims.

In Fig. 5 I show the relative positions and attachment of my improved device and the several parts thereof as applied and used upon an emery-wheel grinder. The emery-wheels A A are mounted upon a main shaft, l3,which is supported within the bearings O. The pulley Dis also mounted upon. the shaft B and revolves the shaft and wheels by a belt which communicates the power. Twolongitudinallyslotted shelf-pieces,E E, project from the bed of the machine to the front. Thus far I have described a common emery-wheel grinding-machine, to which my grinding devices are attached.

The base F has a T-shaped slot, Fig. 1, into which enters the head and shank of the clamping-bolt G, by which said base F is adjustable upon and fastened to the slotted shelf-piece E of theemery-wheel grindingmachine. Asocketpiece, H, integral with the base F, extends upward and has a central bore and open lips, a, Figs. 1, 3. The standard I enters the socketpiece H and is supported thereby and has a horizontal rotary motion therein. W'henturned to the desired position, the standard I is fastened by means of the set-screw b, which, passing through the lips a, draws them together and binds the socket to the standard. The head-piece J (shown in Figs. 14 and 15) is in tegral with the standard I. It has a vertical groove, 0, in which a block, K, is adjustable by means of a longitudinal slot, as seen at d, and a stop screw-clamp, e. By loosening the screw 6 the block K may be placed in any desired position in the groove 0, and then be held securely in such position by tightening the screw e again.

On the side of the head-piece J, opposite to the groove 0, I put a beveled block, L, Figs. 3, 12, 13, 15, and hold it to the headpiece J by the screw f, whose inner end is square and flush with the bottom of the groove 0.

The body-plate M, Figs. 2, 3, l2, 13, has a dovetailed channel for the reception of the beveled block L, and a gib, g, with the screw 1'), takes up the wear of the same. A fixed clamp, N, is integral with the body-plate M, and has a horizontal V-shaped groove or channel throughout its length, Figs. 3,13. Two fixed pins, 0, extend from the clamp Ntoward the front andsupport the movable clamp N, which is mounted thereon by suitable bores, through which the pins 0 pass. The clamp N has a V-shaped groove on its inner surface, Figs. 3, 13. A screw clamping-bolt, P, hasa right-handed screw-thread, i, at its end and a left-handed screw-tl1read, j, on its shank,midway to the head. The clamps N N have female screw-threads to correspond. By turning the screw 1? these reversely-turned screwthreads give a double action, which cause the clamp N to rapidly approach to or separate from each other to hold in place and grip the drill Q, Figs. 2, 3.

The main bar R is connected with the clamping-block N. It has on its front; side a lougitudinal groove, k, Figs. 1, 3, in which a keypiece, Z, fits and slides, Fig. 4.

The chuck-block S has a channel, Fig. 4, by means of which and the key-piece i it is confined to a direct horizontal movement along the main bar R. A thumb-screw, T, passing through a boss on the side of the chuck holds the chuck S in its adjusted position on the main bar It. The chuck S has an upright drillstop, at, and two laterally-projecting horns, 'n a.

A feed bracket, U, Figs. 1, 2, 4, is fastened to the under surface of the main bar It. It has two lugs, o 0, through which the feedscrew V passes. A sliding nut-block, W, is mounted and travels on the feed-serew V. The screw V has a disk or wheel, p, on whose rim is an index. An indicator or finger, q, extending from the lug 0, lies over the rim to mark the degree of the turning of the screw.

The nut W has a stud-screw threaded at its end. The connecting-rod X has an eye by which it is fitted upon said stud, and a nut. Y, secures it in place. The connecting-rod X is pivoted to the block K by the screw-bolt Z.

- The drill-holder A Figs. 2, 4, hasa central bore or opening and a stem, through which a thumb screw, B passes. It also has a side rib, r, of such size and shape that when it lies upon the upper surface of the horns n n of the chuck S alternately the holder describes (in turning the drill Q) an arc of one hundred and eighty degrees. The screw B presses against the drill, and the holder is thus held firmly upon it to turn it as desired. A lever, 0 turning on the screw 8, is mounted upon the end of the headpiece J. At its lower end it has two steps, it. A guide, D Figs. 2, 3, 5, 6, 12, consists of aspring-stem, u, at the smaller end of which it is fastened to the clamp N by the screw 12. The plate of the guide D has its lower edge beveled. (See Fig. 6.)

Figs. 7 to 13, inclusive, illustrate a supplemental drill-holder, which is used to hold drills which are of too small a size to be properly gripped by the clamps N N. It consists of two clamping-bars, E E connected at each end by cross-plates 10, Fig. 12, having a central hexagonal opening and secured to the upper bar, E, by the screw y. The cross-plate isinserted in a groovemade in the end of the upper bar, E and slides in a similar groove in the end of the lower bar, E. The connection of these parts is fully shown in Figs. 10, 12, and 13. The clamping-bars E E are each longitudinally channeled by a V shaped groove, and in a narrow groove on each side of said V-shaped channel a U-shaped spring, 2, is mounted by means of pins to. These springsnormally bring the two bars E E of the clamp together. A handle, I)", projects at one end of the clamping-bar E and has a fixed stop pin, 0

Operation: To grind the lips of the drill, I first. adjust the drill-grinding attachment, Fig. 1, to the slotted shelf E of the grinder and secure it in the required position by the bolt G. I then swing the grinding attachment into the proper angular position relative to the grinding-wheel, Fig. 5, by rotating the standard I in the socket H and confining it in place by the set-screw b. I then insert the drill through the holder A and between the clamps N N, for which purpose I open the said clamps by unscrewing the clamp-screw P, which causes the movable clamp N to move along the pins 0 outwardly. The drill Q," which is to be ground is laid in the V-shaped channels of 8 said clamps loosely with one hand, and with the other hand I press downward the gage D I then determine the proper location of the drill Q, in the machine by bringing into contact with the beveled edge of said gage that corner of the drill-lip which is formed by one of the extreme edges of the flute with the extreme outer edge of one of the lips. cation or adjustment of the drill in place determines the proper line in which to advance the drill to the grinding-wheel, so as to present the lip in the desired relation to the grinder. This location of the drill in the clamps having been determined in this manner, I relieve the gage from the pressure of my hand, and the gage rises by the resilience of its spring, to its former elevated position, where it is clear of the drill. I now advance the drill in a straight line without turning until the lip which is to be ground comes against the grinding-wheel. I then slide the chuck S along the main bar It until its drillstop m bears against the end of the drill-shank. The drill is now properly located and the clamps N N are closed firmly on it by screwing up the clamping-screw P. I next turn the holder A loosely on the drill till said holder is in the position shown in Figs. 2 and 4, and then tighten the screw B until it firmly grips the inclosed drill. The rib 1' of the holder A now lies on the horn a of the chuck S. Iproceed to grind the drill in the same manner as described in my said pending application for Letters Patent. In the present device, however, I dispense with the linkconnection there shown, and substitute for it the beveled block L701] which the body-plateM slides as the end of the main bar R is raised or depressed. The block K is adjusted in the groove 0 of the head-piece J, Figs. 14, 15, as hereinbefore described. The serew-bolt Z, by whichthe connecting-rod X is pivoted to the block K, forms a fixed center of oscillation, and when the main bar B is depressed the body-plate M, having the dovetailed channel, slides forward, carrying with it its connected parts. This movement gives to the lips of the drill the eccentric or parabolic curving motion which is necessary in grinding the lips down to a This lo-- proper edge and clearance. The degree of such grinding is determined by the feed-screw V, turned by the disk 1) to the desired point on the rim of the disk in relation to the finger 11. By this means one lip of the drill is ground, and it is necessary to grind the other lip correspondingly. For this purpose I withdraw the feed-screw V to its former position, elevate the end of the main bar Rto swing the drill-point away from the wheel A, and then turn the holder A over to the position shown in dotted lines in Fig. 2, bringing its rib 9' up on the horn a of the chuck S. This movement turns the drill Qover one hundred and eighty degrees. I then proceed, as be fore, to grind that lip, and obtain the same curve and clearance by turning the feed-screw V again to the same point on the index of the disk 1), as before. If, however, the drill to be ground is too small in diameter to he properly held in and presented by the clamps N N to the wheel A, I use the supplemental drill-holder. (Shown in Figs. 7 to 13.) The insertion of the drill therein is fully illustrated by said figures, and in Figs. 12 and 13 is shown the manner in which such holder is inserted and held in the clamps N N. It is so placed in said clamps that the pins 0" of the handle 2) lies against the end of the clamp N and serves as a stop. WVhen this holder is used, the holder A is dispensed with. To turn the drill one hundred and eighty degrees, the holder is withdrawn, turned half over, and inserted again in the clamps N N; but the stop-pin 0" now strikes against the clamp N.

The office of the lever G is to snpportby its steps i i a lug of the body-plate M, resting upon said steps. The lever is swung upon the screw 8 to engage or disengage at will the body-plate from either of said steps. By this means the machine can be left properly supported in either position.

I claim as a novel and useful invention and desire to secure by Letters Patent 1. The combination of the head-piece .I, having the groove 0, the sliding block K, having the slot 2, the screw (2, the screw-bolt Z,

and the connecting-rod X of a drill-grinding attachment, substantially as described.

2. The drill-holder A herein deseribed,having a central aperture and a stem, a thumbscrew, B", passing longitudinally through said stem, and a rib, 0 upon one side of said stem, in combination with the chuck-block S, having horns nand drill-stop m, and which is adjustable upon the main bar R of a drill-grind ing machine, substantially as specified.

3. In a drill-grinding attachment, the combination of the grooved clamps N N, mounted and operated, substantiali y as described, and the guide D having a spring-stem, 11-, as and for the purpose specified.

i. The combination of the headpiece J, having the groove 0, and the beveled block L, the slotted sliding block K, the screws cf, the rod X, the nut and stud NV, the main bar R, the feed-screw 'V, the disk 1), the finger q, the feed-bracket U, the lugs 0 o, the channeled body-piece M, and means for drillelamping, substantially as described.

5. The combination of the head-piece J, having the groove 0, and the beveled bloelc L, the slotted sliding block K, the screws 6 f, the rod X, the nut and stud IV, the main bar It, and the channeled bodypiece M, substantially as specified.

6. In a drill-grindingattachment, the lever C", having steps t l, and mounted by the screwpivot s on the head-piece J, substantially as and for the purpose specified.

7. In a drill-grinding device, the combination of a headpiece, a main bar provided with drill-clamping, drill-feeding, and drillturning mechanism, a block fixed to said headpiece, a body-piece channeled to receive said block, a connecting-rod pivoted at one end to the main bar in the plane thereof and vertically adjustable at its opposite end upon said head-piece, substantially as described, and for the purpose specified.

FRANK MOSSBERG.

\Vitnesses:

ALBERT D. BEAN, WARREN B. PIERCE. 

